Method of preparing prolamine plastic compositions



Patented Feb. 8, 1944 UNITED STATES PATENT OFFICE METHOD OF PREPARINGPROIIAMINE PLASTIC COMPOSITIONS Harry Weber, Chicago, 111., assignor toAmerican Maize-Products Company,

a corporation of Maine -No Drawing. Application November 4, 1940, SerialNo. 364,297

11 Claims. (Cl. 106-152) The present invention relates generally to amethod of preparing a prolamine plastic composition. It has particularreference to plastic or.

of my prior application Serial No. 124,461, filed February .6, 1937, nowabandoned.

In Serial No. 247,367, I disclose the dissolution of zein in shellac bymastication of zein and shellac on hot rolls. Other natural resins orlike materials have solubility for min. This solubility is alsoexhibited by extracted components of such natural resins, and byderivatives of the natural resins or of their said solvent components. Ihave also disclosed the use of such resinous materials with and withoutnon-resinous solvent mate-- rial to make thermoplastic and normallyviscous to solid zein solutions.

' It is an object of the present invention to prepare solutionscontaining dissolved zein, in which liquid or solid solvents for zeinare used, whether or not natural resin lik'e materials, components ofthem, and their derivatives, are included in the solvents for the zein.

It is also an object of the invention to heat, or

soften or melt the solvent or solvents employed, particularly any ofsaid resin-like materials, and

to dissolve zein in the softened or melted or liquid solvent substanceor substances.

. It is an object of the invention to use a heated solvent or solventsfor zein and to incorporate zein-into the solvent or solvents to obtainsolutions which are plastic when hot, and which may be cooled toviscous, soft or hard solid solutions, as a base which is readily cut ordistended by larger quantities of a liquid solvent'or solvent mixture toform viscous to liquid zein solutions.

It is a further object of the invention to incorporate plasticizers, orto use solvent plasticizersfonzein, for the resulting solid or viscoussolution of the zein, which results fromccoling the heated mass obtainedin effecting the desired solid solution of zein,

It is a special object of the invention to prepare such solutions ofzein which have less than 7 parts of 'water to'93 parts of zein byweight, such as substantially anhydrous solutions.

. It is a further object of the invention to provide a solid solublebase containing protein and mixture, and of the New York, N. Y.,

natural resins, or components thereof, ortheir derivatives.

Various other and ancillary objects and advan- I tages of the inventionwill be understood from the, following description and explanation ofthe invention. v

Heretofore, where zein is used to produce solutions, such as viscousprinting inks, printing ink base, liquid coating and impregnatingcompositions, it has been the customto use dry solid zein and liquidsolvent. To make aviscous solution directly, suchzein dissolvesslqwlyand withdimculty, often forming lumps, and this is truev with somesolvents or solvent mixtures where liquid Manycoating compositions arethe objective. such uses of zein call for resinous ingredients, or

- plasticizers, or solvent, plasticizers, or high-boiling solvents, orsome or all of these in various combinationsin addition to easilyvolatile solvents, or slowly volatile'f solvents.

The present invention is based upon the discovery that zein/may beEdissolved to form a solid solution which may be provided as a viscous,soft or hard, thermoplastic solution of high zein content, for use tomakemore dilute viscous-or liquid solutions, with more speed and easethanwhen using zein in an undissolved state.

. According to the present invention zein, orcom protein containingzein, or any other prolamine, or protein containing a prol-amine, isused preferably" in a finely divided form-in a manner exposing it to ahomogenizing mixing procedurewith solvent material activatedifnecessary, to exert strong solvent power. For example, rosin, 1

shellac, abietic acid and the like which are normally solids, require anactivation by softening or melting by heat, or by distending the same byuse of some liquid to produce a plastic or liquid form. This liquid orplastic form of such solid materials, or any normally liquidv or plasticsolvent for zein, or prolamine, is compounded 'to homogeneity, whereby asolvent action is exerted on the prolamine to formeventually a solidsolution. Mastic'ating .rolls or heavy duty: mixing equipment ,are thepreferred means for attaining this condition, 'andthey are preferablyheated to increase the temperature of the solvent or solvent plasticsolution being formed therewith. I

Compositions normally solids when cold'may thus be obtained which softenat an elevated. temperature, The 'solutionm'ay be formed at an elevatedtemperature to provide a hot plastic mass which may solidify on cooling.Solids thus obtained may be high in dissolved protein-'constituted forthe zein. l

handling, such as tbeprop ertyh;

tent. -Such solids a's lumps, flakes, or powder, with and without heat,maybe more readily distended to more dilute solution, from'viscous toliquid form, by contact with liquid solvents, than can solid zein; Whileit is possible to refer to dis: solving such solids in a liquid solvent,it is perhaps more proper to refer to cutting the solid solution with adiluent solvent. By this methodsolventresin is plastic or even melted.The zein zein, for example, may be dissolved, by flrst compounding'zeinto a solid solution, andthen distending the solid solution by use of aliquid solvent.

Whereas my prior applications referred to g class of prolamines.Consequently, the invention in detail is illustrated byspeciflcreference to zein, with the intent not to limit it to zein, and with theintent that other prolamines may be sub- Posaible advantages. are inreduction in weight for shipping purposes, higher solid content forgiven purposes, such as printing ink base, thermoplastic adhesives andthe like.

When'zein is dissolved in shellac on hot rolls. the process ispreferably carried out in a. short time and atnot tooi higha'temperature, owing to a reactivity between the zein and some activecomponents of shellac. 'I'his reactivity ofshellac resembles thatforming many synthetic resins, in

readily dissolves insuch plastic or melted resins, and the solution maybe cooled to a setting point without throwing out the protein, thesolution being stable at 70 F. against the separation of zein. Thus, inthe solidified cooled masses, the resin is in fact a. solid solvent ofthe zein. The product acquires a shellac-like toughness, which is a'property that has long been sought for in the field of synthetic resins.The product has Y solubility in many common s lvents, and solutions ofit are superior to dis olved shellac for the common uses of shellac..-Solutions of it have many uses for which a solution of shellac is notentirely satisfactory. For example, solid solutions of the presentinvention were dissolved and applied as a varnish. The application driesquickly without tackiness in a shorter period, to a highly adherent andtough coating. This coatingmay be' sanded very soon-after completion ofthe drying and in a much shorter time than a,

shellac coating. The composition as a olution in .a volatile solvent hasless penetration, and bone more covering power.

As Example 1; a highly absorptive tissue paper was coated on one sidewithout destroying the absorptive value of the body of the paper, by amass containing'by weight parts. of zein, 20 parts of rosin and 25 partsof plasticizer (Santicizer 8) dissolved in 270 parts of commercialdenatured alcohol.

that it exerts a thermo-setting action, and produces a hardening,toughening and a lowering of the solubility of the combination product.For

. this reason'where the rolls are heated by lb.

steam pressure, the incorporation of zein into shellac is preferablyeffected in at least 15 minutes. Time may be shortened, or temperaturemay be lowered by moistenlng the plastic mass fferred for this purpose,as this is readily 10st,. P

I have found that the property of dissolving Coatings of the solidsolutions are comparable in toughness to'coatings of non-analogoustypes, such as cellulose derivative lacquers. The latter are. commonlyused where toughness is desired, but] in many uses the surface exposedlacks desired. properties such asprintability with oil-base printinginks. Coatings made of the solid-solu tions of the present inventionhave such print ability. In the same field they have freedomfrom'off-setting. Colored coatings have been used to give a white sheetthe appearance of a colored'sheet, and then the color-coated sheet,

I. may. be printed upon the same as a colored uncoated sheet. Thecoating has'also been applied zein is not peculiar to shellac, and thatit is d\by other natural resins, such as rosin. pontianac, elemi, congo,manila, and dammar. I have-also found that components of these resins(such as abietic acid from rosin), which are commonlyextracted from themfor use in commerce,

also have this property. And further; I have 'found 'that derivatives ofthe raw resins, and of their components have thesame property.' Debeingknown as Albalyn, made by Hercules Powder Company. Wilmington. Delaware)shows solubility for zein. This is an ester with a inonoliydric alcohol.mm with polymeri alcohols also have I have also found that therefis atendency for peraturol. -The reaction is slow and-does not interferewitha moderately. hasty procedure for or without color in the coating. Suchcoatings have also been applied to asphalt impregnated products torender them bleed-proof" and eliminate any inherent tackiness of suchproducts.

The composition may also be worked up with solvents, to form inks withor without plasticizers,

forv intaglio printing, screen-stenciling, letter- Jpress, oifset,sign-making, painting, and, such uses. By the-incorporation of inertmineral or fibrous fillers, compositions suitable for thermoplasticmolded products can be produced.-

The thermoplastic compositions may also be appliedidirectly to paper,wood, fabric, etc, by means of suitable heated rolls. In general, the,

' compositionshave the drawback of stringing u m ruin {preset-withthezein at elevated temwhenapplied in this manner, resulting inltheapplication "of an'unevencoating. Hot calendering of such unevencoatings improves the surface materially.' The incorporation of minorviscous composition that can be readily applied to surfaces to coated bymeans of a doctor" q blade or sprea ng knife. In this manner, as well asvolatile solvent solution thermoplastic eifecting solution attemperatures where the coat; gs for solids have beenproducedin whichremain longer in the mass.

. 2,340,913- the coating is subsequently used as a heat-sealingadhesive.

As one'example of this type of'composition, the following is given:

EXAMPLE 2 Parts by weight Rosin 175 Zein 390 Diethylene glycol orethylene glycol 150 Santicizer 8 110 190 proof denatured alcohol (5%methanol) 1'75 Titanium dioxide"(titanox) The titanox was ground in apebble mill in the alcohol, thoroughly to wet the pigmentand reduce itto the desired fineness, and the product' added to a heated mixture ofthe other ingredients previously mixed in a heavy duty mixer. Theresulting. viscous solution is stable against separation of zein orgelling at 70 F. It was coated on paper box board, the distribution andthickness of the coating being regulated by an adjustable doctor bladeor knife and passed through a hot-air chamber to remove the volatilesolvent. An opaque, white coating having a high gloss was produced. Theviscous solution described may be thinned, if desired, as by use of 190proof alcohol, grain or denatured.

In carrying out this phase of the invention any solid solvent is heatedto soften or melt it.

Heating also serves to improve the solvent power of normally liquid orviscous solvents. Finely dividedor powdered commercially dry zein isincorporated into the solvent by appropriate mechanical mixing devices.The zein may contain no moisture or considerable.- moisture, the averagecommercial material having about 7% water. Where resins or high boilingsolvents are used, the water content is largely lostin the process ofincorporation, when the temperature employed is near and usually abovethe boiling point for water. Thus, substantially anhydrous solutions areobtained. If a third agent is present which is a solvent for either orboth of the components, the agent assists in the process. Such liquidagents permit use or lower temperatures and the shorter time for the hotdissolution process, and according toits volatility it is lost in theprocess. For example, where 190 proof ethyl alcohol (grain ordenatured)is used in a quantity up to 20% of the total solids of shellacand zein,the process of incorporation may be carried out with a lessenedthermo-setting reaction between the shellac and zein. On steam rolls(heated by 50 lb. steam pressure) the mutual incorporation may becompleted in from 10 themethyl, propyl and higher homologs are alsocontemplated.

Other high-boiling solvents are ethylene glycol, propylene glycol,diethylene glycol and triethylene glycol. ethers are all equivalenthigh-boiling solvents for the present invention, and it is to beunderstood that where any one of them is given in a forterial changemula, each of the others may be substituted in the formula in the samequantity without main character f the resulting product.

Any of the solvent resinous materials may be used exactly like shellac,with or without an added agent, such as volatile solventyor non-volatilesolvent or a permanent plasticizer, which may be a solvent for the resinelement or the zein, or for both. When plasticizer is used the cooledcomposition may be less rigid, and even flexible, or rubbery. A coldrubbery mass A is formed by a composition having by weight 4 parts ofrosin, 4 parts zein, 1 part Santicizer 8, and 1% parts of ethyleneglycol.

, vent plasticizers for the rosin and the zein.

A hard'tough resilient mass B, rigid when cold, is formed by 4 parts byweight rosin, 4 parts of zein, 1 part of dibutyl tartrate, and 1 part ofethyl ene glycol,-or its equivalents above named. Thus it will be seenthat the properties are greatly affected by the choice and proportion ofplasticizer. The solid product may be cut by 190 p: oof denaturedalcohol, such as 5% methanol-denatured, to form stable solutions at 70which are non-gelling.

A tough mass C, resilient and pliable when cold, is formed by 2 parts byweight of rosin, 2

I vby weight of zein, and 35 parts of ester gum.

parts of zein, 1 part of dibutyl tartrate, 1 part of ethylene glycol, orits equivalents above named.'

Each of the masses. of the above examples were incorporated together at250 F. in about 2 hours in a Baker Perkins mixer.

The solid product may be cut by 190 proof denatured alcohol, such as 5%methanol-denatured,

, to form stable solutions at R, which are nongelling.

A hard tough solid D is formed from 40 parts Ester gum is a partiallyreacted 'product of glycerine (a polyhydric alcohol) and theabietic acidcontent of wood rosin, and is commonly referred to as a glyceride ofabietic acid, the latter to 15 minutes, during which time thethermalsetting property is not expended. Thus, within this, and withinlonger times, a plastic mixture may be taken-from therolls, preferablyin sheet form, and cooled, which mixture is subject to thermo-setting onfurther heating for a prolonged period. Where a medium boiling solventbeing a mono-basic organic acid. The ester gum of commerce has ameasurable acid number,- showing it to be an incompletely reacted ester.This composition D makes an excellent printing ink with 400 to 700 parts190 proof ethyl alcohol (grain or denatured), for intaglio printing. A

distender may be used as set forth below. The solid product may be cutby 190 proof denatured 1 alcohol, such-as 5% methanoldenatured to formstable solutions at 70 R, which are nonagellzng, such as the saidprintingdnk from composition D.

. With only the resinous solvent and the zein, up

' to. of the mass may be zein without much difliculty in the mechanicalprocedure. However 60%- is the preferred safe limit for the process ingeneral. In any case where there is encountered some difllculty ingetting the zein properly incorporated, the addition of an" agent suchas ethylene glycol, eliethylene glycol, ethyl alcohol, Cellosolve or itsequivalents named above, or a plasticizer, as dibutyl tartrate or Theseglycols and their mono-alkyl These two plasticisers are sol- The sameeiTect on. hot rolls can be obtained in about 20 minutes.

Santicizer 8, whethersolvent or non-solvent,

serves to distend the mass and ease the process. 1 Where the agent is asolvent'for one or the other,

or for both, its effect is more marked, and in such case the zein andthe resinous ingredient may be mutually combined in all proportions.Thus, in making the formula of Example 2, the rosin and the zein, thezein being about 69% of the rosin and zein, may be incorporated togethermore readily by adding a little solvent such as Cellosolve,'forexample100 parts to the formula, without losing the stability of the solution.

There is some evidence that a thermal reacti' 11 takes place betweenrosin and zein, but it is not as extensive as im the case of shellac andzein. The latter two can react to form a thermo-rigid body, but withrosin andv zein the product is thermoplastic under the conditions whichproduce such thermorigidity.

Just as the resinous solvents exert a solvent action on zein, so do manynon-resinous mate'- rials, such as the Cellosolves, the Carbitols, the

alkylene glycols, and other high boiling organic solvents, and alsocertain solvent plasticizers, such as the aromatic alky latedsulfon'amides, of which Santicizer 8 is the toluene sulfonamide,

others being set forth in Hansen Patent No.

Any of the known solvents for zein or prolamine, or solventplasticizers, which are not read- I ily volatile, may be mixed with dryzein, heated and mastic'ated or otherwise homogenized to exert thesolvent 'power on the protein. However, it is preferred that resin orresinous material also be present, because as a general rule a mixedsolvent for zein has more solvent power than corresponds to the sum ofthe solvent powers of the separate ingredients. Consequently thepreferred examples of the present invention involve a resinousingredient, not-only toimprove solspctting with water than an unbakedfilm, indi-.

ethyl alcohol as a major solvent for commercial zein, brings into thesolution not only the water.

of the dry zein, but also the water of the'alcohol. By incorporatingsuch dry zein with some high-boiling or non-volatile solvent, atelevated temperature, to form a solid solution under-condition's whichdrive awayall or much of the water content 01 the commercial zein, thereis obtained a'substantially anhydrous solid solutionof zein. To this theaddition of 95% ethyl alcohol or 95% non-aqueous solvents of differentcharacter, as-

sures that theflnal solution has less waterthan if the same solvents andcommercial zein were incorporated together by simple procedures ofmixing until dissolved.

The invention is not limited to a kinetic procedure, as above described,for producing solid solutions of zein and a normally solid solventtherefor. This is merely a mechanical way of securing intimate contactbetween'the elements of the mixture. &- static procedure may beemployed. For example, a thin film of rosin, shellac, or other solidwhich dissolves zein, may-receive a zein coat deposited from a zeinsolution. This in turn may receive a rosin coat, or a coat of the solidused, and so on. A built-up mass of laminated zein and rosin, or, othersolid, may be heated to secure the desired solution, and this may bedone under conditions to permit evaporation of any included water. P

. Another static procedure is to dissolveor suspend one element in asolution or suspension of i the other, such as suspending rosin ina-solution' of zein in a solvent incapable of dissolving rosin, oremulsifying the resin'and the zein in a common vehicle. Such a mass isfreed from solvent or liquid and the residue heated. By

baking at C. for 2 hours a deposit of rosin and zein from a commonsolution of them in an ethyl or like alcohol, preferably 190 proof, thebaked film showed a much greater resistance to eating a change in thestructure by the thermal action. Thisis either a change to solidsolution of the zein in rosin effected by heat, or else rigid body withshellac and zein, the process isl carried out under conditions chosen toeffect the incorporation without the thermal reaction preventing theoperations.

Any of the solid or viscous compositions, such as masses A, B, C, or D,given above, may be distended to a'viscous or liquid. coating solution,and applied as [coating solution to paper, plies of wood, or fabric forlamination with heat. solid sheets of the thermoplastic composition maybeinserted between two sheets to be united, and

heat applied {to the assembly. Paper such as glassine, or syntheticsheets such as regenerated 0 cellulose, or cellulose acetate, may be sounited.

In making coating solutions, whether liquid or viscous, a volatilesolvent, such as 190 proof grain or denatured alcohol, or more anhydroussolvent or solvent mixture may be added to the thermal y produced solidsolutions above described.

The olvent readily cutsthe' protein solution already present so that onstanding or by applying heat, the solid substance goes smoothly into anew, and diluted solution without. danger of lumping or other dimculty.One great advantage of this procedure is in the production of a.soluthan havinga high content of zein with a minimum of aquosity.Considering that commercial zein contains about 7% of water, the'use'of96% it is the creation 01a new product by a.- reaction of rosin and minunder the influence of heat,-or it may be 105s of residual water. Theheat effects anew condition not heretofore presented by the compositefilmformed by evaporating a mutual solution of the two ingredients. Thesolution may also contain plasticizers or'high boiling solzientmaterials like the heat-masticated composi- In this specification and inthe following examples where "95% alcohol isusedfkit is intended Z thatthis maybe 190 proof grain (ethyl) alcohol, or 190 proof denaturedalcohol. Denatured alcohol is intended to mean ethyl alcohol dena- 0\.tured according to any of the standard government formulas,and any ofthe common commercial formulas. Some of these are compounded as follows,and are identified by the terms com-- monly used in trade.

s. D. No. 1 (aut orized composition) Y To 100 gallons of 95% (by volume)ethyl alcohol, add 5 gallons of approved wood (methyl) alcohol (95% byvolume).

Resultant volume at F., 105.1 gallons.

(Sala 01' Shellacol {authorized compositionr Solox i manufactured 'by U.s; Industrial Chemicals, Inc., New York city, N. Y., and Shell- SolventsEthyl acetate gallons Aviation gasoline do- 1 Resultant volume at 60 F.,106.0 gallons. Zein solutions in alcohol and like solvents, but withoutrosin or other natural or synthetic resins, are subject to varying lifeas to their stability at 70 F. They'may slowly' gel. I have found thatwhen these solutions are changed by including rosin, or natural orsynthetic resins, they have increasedstability. Lactic acid is aningredient acting like resins for such function.

Therefore, the combination of resin and zein in the form of solidsolutions according to the present invention affords a form of zeinadapted for making zein solutions of high stability.

The following useful compositions may be made directly from theingredients by heating if required, but preferably by using thezeincontent of the formula with one or more of the resins, plasticizers, orhigh-boiling solvent components, to form viscous or solid solutions, andthen cutting the solutions with the more liquid ele ment or mixture fromthe formula. Where the viscous or solid solutions are made in the mannerherein described, temperatures at or above 212 F. are preferred in orderto remove water, particularly that accompanying commercial zein, to makesolutions of lower aquosity.

ExAMPLs 3 Parts by weight Zein 40 Sheliacol 200 Resyl 132-3 20 Carbitol0.5 Lactic acid (100%) 4 to The lactic acid has been used as a 50%solution,

against separation of zein at 70 F.

Exmm 7 g Parts by weight Zein 1o Shellar'nl 50 Lactic acid (85% 2 Theabove solution is stable and non-gelling'at 70 F., and makes anexcellent glaze coating for candy. If caustic soda is added in quantityto neutralize part or all of the lactic acid, sodium 'lactate isformed-which serves as a plasticizer for the zein.

EXAMPLE 8 g 7 Parts by weight Zein 10 Rosin I 10 Ethylene glycol 2 Oneof the following:

(a) Dibutyltartrate 2 (b) Santicizer 8 2 and as an 85% solution inwater, the common commercial grades. Resyl 132-3 is an alkydresin madeby American Cyanamid Company. The above composition is non-gelling andstable against separation of zein at 70 F.

Diethylene glycol Rosin r 175 76 She The above formulation isincorporated by heat to forma solid solution, which is slightly plasticwhen cold, and'capable of being sheeted, and is self-adhesive at summertemperatures. This solid has been taken up in 95% alcohol (grain ordenatured) in varying quantities. In the form of a 25% solution ofsolids, these solutions have EXAMPLE '9 a Parts by weight Zein 20Denatured alcohol such as Shellacol 80 Methyl Cellosolve 0.2

The above solution is substantially non-gelling and stableat 70 F. forcoating paper, and other surfaces.

EXAMPLE 10 Parts by weight zein; 2o Denatured alcohol 140 Benzol ..s 20Gum mas c 20 The above solution is non-gelling and stable at 70 F.

The above composition is non-gelling and EXAMPLE 11 stable againstseparation of zein at 70 F. It has Parts by weight been usedsuccessfully as a priming coat for fur- Zein 50 nitu-re. Absolute ethylalcohol 210 EXAMPLE 5 Water 10 I Partsby weight Dibutyl tartrate 25 ZeinThe above solution is non-gelling and stable Denatured alcohol(including methanol) 401 at R Santicizer 8 v 1 Exmnlmh h y glycol 1 IParts by weight Rosln 4 z in 5 1A mixture of orthoand para-toluenesultonamides 65 Denatured 8.1001101 made by Monsanto Chemical Company, St. LouiaMissouri. nibtuyl t 8 The above solution is non-gelling andstable Copal gum 40 against separation of m at Y The above solution isnon-gelling and stable EXAMPLE 6 at 70 F. v Parts by weight EXAMPLE 13Zein 390 I Parts by weight I Shellaml 175. z m 30 Denat ured alcohol jThe above solution is non-gelling and stable The solvent may be 95%ethyl alcohol, 95% alcohol having methanol as denaturant, 95% -M DIYIalcohol, or 95%-mono-ethyl ether of ethylene glycol. The zein may havefrom 0 to about 7% moisture, the latter being commercial.

zein. The plasticizer may be dibutyl tartrate, Santicizer 8, tricresylphosphate, dibutyl tartrate, triacetin, aromatic and aliphaticsulfonamides (including Santicizer 8), and other well known onescommonly 'used in shellac, prolamine-base compositions, or other basecompositions which are commonly deposited from volatile organicsolvents, such as lacquers. I

Solutions according to this example are stable against separation ofzein and non-gelling at 70 F.

The shellac, 'zein and plasticizer may be incorporated together by heatto form a solid solution, and at elevated temperatures, such as at 212F, or higher water from commercial zein will be lost. Or the zein may bedissolved in about two-thirds of the alcohol, and the shellac in theremainder. Plasticizer may be added to either or both such separatesolutions, o to the two solutions after combining. Denatured alcohol orother solvents for the formula, and many others, may be added to dilutethe solution.

The coating composition as given, or as diluted,

has been applied as a priming coat to natural wood, such as furniture,to be finished with paint,

varnish, lacquer or more of the same priming composition. It may be usedto coat or impregnate paper, cardboard, printed paper or cardboard,cloth, shaped material entering into shoes,

hats, coats, furniture and the like, book-backs,

paper book-jackets or coversfmagazine covers, advertising sheets,labels'and the like.

The solution is ideal for use on printed paper sheets used as protectivejackets for the fly-covers of books. These are usually printed on oneday and shellac-coated on the'next. Oxidation of oils in certainprintinginks often creates heat in stacks of shellaced printed sheets and thisfrequently causes sticking within the stack. Use

of the above compositions prevents such sticking. Heat hardens the coat.

EXAMPLE 28 f Parts by weight Zein p 23 Absolute ethyl alcohol- 55Toluene 24 Cellosolve 21 Rosin The same solvent composition has beenused to dilute the above formula to coat paper. The above and thediluted solutions are stable and non-gelling at 70 F. r

EXAMPLE 29 a This solvent is disclosed in my application Serial No.247,367.

I Parts by weight Zein 23 Absolute methyl alcohol 70 Toluene 30 Rosin;10

The same solvent composition has been used to dilute the above formulato coat paper.

The above and the diluted solutions are stable and non-gelling at 70 F.

In' all of the foregoing examples it is to be understood that where thezein is made up to solid or viscous solution thermoplastically, each ofthe formulas: may be modified by the use of distenders as above named,and theequivalents thereof above named. Therefore, each formulation isto be read and is considered as given herein, with such modification,the amount used for distending being small for the purpose, as required,relatively to the total formulation.

. The various modifications .suggested, and others,

' are contemplated as falling within thescope of the appended claims.

I claim: I

1. The method of producing a substantially anhydrous solution of zeinwhich comprises homogenizing commercially dry zein having about 7% byweight of water at an elevated temperature above theboiling poin't ofwater with a substantially anhydrous organic material which is a solventfor zein at the temperature so employed, which material is characterizedbyfluidity at said temperature and which is further characterized by theability toretain said fluidity against boiling at the temperature soemployed; and permitting substantially all the Water content of vmassrat the temperature so employed which mass the zein to evaporatefrom'the resulting mixture during said homogenizing, the relativequantities of said zein and said solvent material being such as toprovide a substantially anhydrous plastic on cooling to normaltemperature provides a substantiall'y anhydrous thermoplastic non-liquidsolution of zein.

2. The method of p roducing a solution of 'zein' which compriseshomogenizing commercially dry zein having about 7% by weight of water atan elevatedtemperature above the boiling point of water with'asubstantially anhydrous organic material which is' a solvent for zein atthe temperature so employed, which material is characterized by fluidityat said temperature and which is further characterized by the ability toretain said fluidity against boiling at the temperature so employed, andpermitting Water to evaporate from the mass during said homogenizing,the' of less water content than is obtainable by direct solution of saidoriginal zein in the same ultimate solvent ingredients, and cooling saidplastic mass to provide said non-liquid solution.

3. The method of producing a substantially anhydrous solution ofprolamine which comprises 1 homogenizing commercially dry prolaminehaving about 7% by weight of water at an elevated temperature above theboiling point of water with'a substantially anhydrous organic materialwhich is a solvent for prolamine at the temperature" so employed, whichmaterial is character ized by fluidity at said temperature .and which.

is further characterized by the ability to retain said fluidity againstboiling at the temperature so employed, and permitting substantially allthe water content of the prolamine to evaporate from the resultingmixtur during said homogenizing, the relative quantities of saidprolamine and said solvent material being such as to provide asubstantially anhydrous plastic mass at the temperature so employedwhich mass on cooling to normal temperature provides a substantiallyanhydrous thermoplastic non-liquid solution 01' prolamine.

4. The method of producing a solution oi prolamine which compriseshomogenizing commercially dry prolamine having about 7 by weight ofwater at an elevated temperature above the boiling point of water with asubstantially anhydrous organic material .which is a solvent forprolamine at the temperature -so employed, which material ischaracterized by fluidity at said temperature and which is furthercharacterized by the ability to retain said fluidity against boiling atthe temperature so employed, and permitting water to evaporate from themass during said homogenizing, the relative quantities of said prolamineand said solvent 'material being such as .to provide a plastic mass atthe temperature so employed which mass on cooling to normal temeratureprovidesa thermoplastic non-liquid solution of prolamine havingproportionately to prolamine less water than the Original form ofprolamine employed, which latter solution is readily distendable bycontact with normally liquid solvent'ror prolamine to form a liquidprolamine solution oi less water content than is obtainable by directsolution of said original prolamine in the same ultimate solventingredients, and cooling said plastic mass to provide said nonliquidsolution. 7

5. The method of producing a solid solution oi. prolamine whichcomprises homogenizing moisture-containing prolamine havingat least 7parts by weight of water to'93 parts by weight of prolamine atanelevated temperature above the boiling point of water with asubstantially anhydrous organic material which is a solvent tivequantities or said prolamine and said solvent material being such as toprovide .a plastic mass at the'temperature so employed which mass on forsaid prolamine at the temperature so em-- ployed, which material ischaracterized by fluidity at the temperature so employed and which isfurther characterized by the ability to retain said fluidity againstboiling at the temperature so employed, and permitting water toevaporate from the resulting mass "to provide less than 7 parts byweight of -water in said mass to 93 parts of prolamine during saidhomogenizing, the rela-' cooling to normal temperature provides athermoplastic non-liquid prolamine solution.

6. The process of claim 5 in which the solvent material includes rosin.

7. The process of claim 5 followed by distending the resultingthermoplastic prolamine mass in a substantially anhydrous normallyliquid solvent for prolamine in quantity to provide a normally-liquidsolution 61 prolamine.

8. The process of claim 1 followed by distend-- ing the resulting zeinmass in a subs antially anhydrous normally liquid solvent for ein in-quantity to provide a substantially an ydrous normally liquid solutionof zein.

9. The method of producing a solid solution of zein whichcompriseshomogenizing moisturecontaining zein having at least '1 partsby weight of water to 93 parts by weight of zein at an elevatedtemperature above the boiling point of water with a substantiallyanhydrous organic material which is a solvent for said zein at theprovides a thermoplastic non-liquid zein solution.

l0. The'process of claim 9 in which the solvent material includes rosin.

11. The process or claim 9 followed by distending the resulting zeinmass in a substantially anhydrous normally liquid solvent for zein inquantity to provide a normally liquid solution of zein. v

HARRY M.'WEBER.

